Saturday, February 26, 2005

Food Science: making your dinner tasty.

One of my early jobs was in the now-defunct Food Science Department at MIT. Here are some projects I remember:
  • Improving the mouthfeel of artifical fruit-like gel matrixes. I could not find a whisper of this work now, it's probably completely outmoded.

    What is Mouthfeel? Citations from the Word Spy:

    Lipton product manager Stuart Miller says ice cream on stick normally lasts customer age 6 to 12 between 4 and 7 minutes, but no-drip ice cream lasts 8 1/2 to 9 minutes; key to no-drip ice cream is new 'stabilizer' that promotes bond between water and fat in mixture and does not affect quality, texture, taste or mouth feel (The New York Times, August 26, 1973)

    Another option is No-Cream Cream. It's a recipe from the Fetzer Vineyards Food and Wine Magazine, which the winery published several years ago. The "no-cream" is an excellent ingredient that can be added to most any savory soup or sauce when you want to simulate the richness and mouthfeel of cream without the added fat or calories. (Sun-Sentinel, August 1, 2002)

    Anyway, fruit-like gel matrixes are, for instance, fake blueberries in breakfast cereal. Problem: instead of being juicy like cucumbers when you chewed them, the artificial fruit-like gel matrices got DRYER inside your mouth. Did MIT improve this product? Any eaters of articial blueberries, please report back to me.

  • Shear flow in salad dressing. What you want in a salad dressing is that it pour easily from the bottle, but thicken up and sit in a plump little blob once it hits the salad. This work was sponsored by an oil company. Here is some recent work:
    Agriproducts Inc. has been developing new applications of its No. 1 product, gum arabic... gum arabic systems are used to emulsify and impart smooth, creamy mouthfeel ... In addition to nutraceutical applications, where the gums suspend and emulsify particulates, these gums are used in pourable salad dressings from reduced-calorie products to "standard-of-identity" french dressings.

    "It imparts great 'clingability' to the products, including our systems," he says. "Manufacturers want dressing to cling to cold lettuce, not to pool in the bottom of the plate. Our products are satisfying that need without getting gummy or gloppy, maintaining smooth rheology and still imparting good cling."

    Shear Flow, cont.

    "The same sample can exhibit drastically different behaviors depending on the handling. Viscosity is a fluid response to shear flow, where shear flow may be visualized as rubbing two hands past each other with a sample between them. ... The speed of rubbing is related to the rate of shear. ... Fluids with large extensional viscosities are said to be “stringy.” Therefore, depending on the type of force applied to a fluid, the same fluid can be independently viscous and stringy.

    "'Too stringy' is a frequent consumer complaint about these products: The product does not break cleanly when the container is maneuvered to stop flow, i.e. a stringy filament strand forms from the lip of the container (Clark, 1997). This property - extensional viscosity - is a measurable rheological parameter of fluid foods, contributing to texture."

  • "Enhancing" shelflife. My bosses were working on a system which would keep potato chips viable for years. Perhaps centuries. See previous post on bread shelflife.

Here are a few tidbits from today's food sciences industry. Working to make your food tastier. Just skip along to the next post if it's too much for you.

  1. From a study supported by the California Dairy Research Foundation:

    Our group is investigating transport into and out of micelles, particularly as it occurs within complex systems such as emulsions and gels. Surfactant aggregates known as micelles have a profound effect on the rate at which oils and other hydrophobic solutes are transported out of oil droplets within emulsions, and this transport has a major impact in such areas as food stability, flavor perception, and oil metabolism within humans.

    Equilibrium partitioning experiments allow us to determine the relative affinity of the different components of whey proteins for the reversed micellar phase, and to explore how differences in protein size and hydrophobicity, as well as protein charge, affect their solubilization within the microemulsion. One interesting outcome of this research was the discovery that the smaller of the two milk proteins, a-lactalbumin, has a substantial effect on the properties of the microemulsion phase, suggesting that this small, interfacially active protein may act as a "cosurfactant" and aid in the formation of the microemulsion phase. This observation gives rise to the possibility of using proteins such as a-lactalbumin to aid in the formation of biocompatible microemulsions.

  2. From Food Rheology: Instrumental and sensory characterization for a texture profile analysis of fluid foods.

    Texture is a criterion by which quality is judged and an important factor when selecting or rejecting products. Therefore, an understanding of food texture is paramount to deliver foods that adhere to consumer expectations. ... In this research project, fluid foods were exposed to a variety of rheological methods, exerting different stresses to invoke unique flow behaviors. Rheological methods included measurements for shear viscosity, biaxial extensional viscosity, an empirical stringiness index, and yield stress.

    ... Clark (1997) conducted a fundamental approach to measuring extensional viscosity for the purpose of discerning the extensional flow of pancake syrups with different hydrocolloids. In this study a fundamental rheological instrument called an opposing jet rheometer was used to study the extensional flow behavior of xanthan and carboxymethyl cellulose (CMC) gums. These two gums are commonly used hydrocolloids in pancake syrup. Sensory tests were not conducted in this study to evaluate extensional viscosity, however the researcher hypothesized the importance of extensional viscosity on pancake syrup texture.

  3. Extending shelf life of fresh minced camel meat at ambient temperature by Lactobacillus dlbrueckii subsp. delbrueckii, by Ichraq Kalalou, Mohamed Faid, and Ahmed Touhami Ahami at Ibn Toufail University, Morocco

  4. On Hydrocolloids and American food design: Hydrocolloids are filling an unprecedented array of needs in food development ...

    "The whole idea of a fluid gel system is very interesting to our customers wherever they're looking for unique means of suspending particulates, ranging from large particulates like a gel bead to finer materials like pulp in home-style orange juice or spices," says Hartnek. "This technology has lots and lots of potential applications."

    The most spectacular new applications of gums and gum systems are coming in the creation of entire new foods. A prime example is Hercules Inc.'s development of a new spoonable dessert, a fruit-flavored flan for which carrageenan provides the characteristic texture and a pectin formulation gives the required stability. The acidified fruit desserts have a creamy, somewhat cuttable texture typical of a neutral-flavored flan. They would be packaged in a cup, like yogurt, but are much firmer than yogurt. The carrageenan used is rather unique since it is much more stable at low pH levels compared with other types, which tend to break down.

    Another new application that Sapone describes is an instant, liquid-based dairy dessert that could be either refrigerated or made shelf-stable in a pouch, retort container or squeeze bottle. A consumer would mix the fruit-flavored liquid syrup with equal parts milk and stir, and within 15 seconds the combination would produce pudding-like textures.

    With new gums and gum systems, FMC's Food Ingredients Division, Philadelphia, is formulating potential new products with unusual textures, as well. "We're following through on the trends toward convenient, ready-to-eat-type products that are portable, handy to take to school, lunch or work," says Jeff Dopf, market segment manager for gels and emulsions.

    "We're trying to look outside the box and see what the consumer is willing to accept," Dopf adds. "That's the approach we're taking: What can we do with these gums?"

    Among the more innovative ideas is the University of Maine's development of a gum system to prevent the bleeding of individually quick-frozen low-bush blueberries in blueberry muffins. ... The problem, as reported by frustrated bakery processors, has been that the berries bleed into the batter, producing grayish-blue streaking that turns off most consumers. ...

    Bakers already had tried applying powdered starch to the berries before mixing them in batter, but it didn't reduce leakage as much as they hoped. In research funded by the U.S. Department of Agriculture and the Maine Blueberry Commission, Bushway and colleagues tried guar gum, gellan gum and gum arabic before settling on the gum that best addressed the problem: carboxymethylcellulose (CMC).

    "Chicken could be dipped into a hot, not very concentrated slurry of [a similar] product ... when the gel dried, it created an intact film. You could create a transparent film or one with a texturized surface that simulated skin by letting it dry on a coarse, uneven surface. The film was not only edible, but could be formulated to be heat-reversible as well."

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At 1:52 PM, Blogger anonyMoses said...

I thought you looked familiar!
I may have seen you when I was living in Cambridge. Were you there between '80 and '86?

You do look familiar to me...


At 11:02 AM, Blogger Badaunt said...

Bloody hell, where is the FOOD in all this?

At 11:07 AM, Blogger Badaunt said...

Oh, and by the way I knew exactly what was meant by 'mouthfeel.' I once lost my sense of taste, completely, for two days. It was incredibly hard to eat, because for two days the only sensation I got from food was 'mouthfeel.' Mouthfeel is fleeting, though. EVERYTHING has the consistency of paste once you've chewed it.


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